Optical phased array architecture for wavefront sensing

An optical phased array (OPA) photonic integrated chip includes a plurality of array elements, a plurality of phase shifters, a plurality of combiners, and an edge coupler configured to couple to a single mode waveguide. The plurality of phase shifters includes a layer of phase shifters that has a phase shifter connected to each array element in the plurality of array elements. The plurality of combiners is configured to connect the plurality of phase shifters to the edge coupler. The plurality of combiners includes a first combiner that has a first output that is connected to a second combiner or the edge coupler, and a second output of the first combiner is connected to a photodetector. An in-phase light portion at the first combiner is output through the first output, and an out-of-phase light portion at the first combiner is output through the second output.